EpubCCEPUBCheck OBS-001: outdated feature in use
Updated:
EPUBCheck OBS-001 is a usage message: “Usage of … is outdated.” The EPUB uses a feature that still works but is outdated. EPUBCheck names it: an NCX, font obfuscation, a manifest content fallback, a deprecated element or property, or a prefixed CSS property or value. It is a usage note.
The official message
Usage of %1$s is outdated.
Variants
content-fallback: manifest content fallback (for resource "%1$s")font-obfuscation: font obfuscationelement: the %1$s elementncx: OPF 2 NCX navigationproperty: the "%1$s" propertycss-prefixed-property: the CSS prefixed property "%1$s"css-prefixed-value: the CSS prefixed value "%1$s"
- Default severity
- Usage. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.
- EPUBCheck version
- 5.4.0
%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.
Typical causes
- Books made for EPUB 2 or older reading systems that keep an NCX or a guide.
- CSS with -epub- or vendor prefixes such as -webkit-, copied from older templates.
How to fix it
- Nothing breaks today, and you can leave it if older reading apps still matter to you.
- When you next update the book, replace the feature with its current equivalent, for example unprefixed CSS properties such as writing-mode instead of -epub-writing-mode.
- Keep an NCX only if you need EPUB 2 reading systems; EPUB 3 apps use the nav document.
When it's not this
If the element is discouraged rather than outdated (base, rp, embed), the note is HTM_055.
Terms used here
Sources
Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.